Above-ground swimming pools typically have a tubular support structure that supports a water-proof liner. For anything other than the smallest pools, the structures are usually difficult to erect and are prone to being damaged. The liner is especially vulnerable. In addition, unless the underlying surface is swept absolutely clean of pebbles and other debris, the liner, once laid in place, will not be smooth, which can be both unsightly and uncomfortable to the touch. If, for example, the liner is inadvertently laid over a rock or pebble, a swimmer may step on the unseen object and possibly injure himself and the liner. Remedying the situation requires a pool owner to drain the pool, remove the liner, and reassemble and fill the pool, which is quite time-consuming.
The patent literature describes a number of above-ground pool, spas, and liquid storage tanks. For example, U.S. Pat. No. 4,974,266 discloses a swimming pool structure for on-site assembly, which comprises a flexible liner supported by a surrounding wall of side-by side wooden staves and a plurality of cables that pass entirely around the pool wall. U.S. Pat. No. 5,054,135 discloses a molded modular plastic framework for a swimming pool, which comprises an endless molded base member having post sockets and a continuous cove, the molded members being connected end to end to make the endless base member. U.S. Pat. No. 5,114,274 discloses a sewage collection and separation tank that uses as hexagonal elastromeric gasket mounted at a groove, with one end of the gasket abutting against another gasket mounted in the side of the sump pit to provide a liquid-tight seal. U.S. Pat. No. 3,971,075 discloses a swimming pool structure comprising a plurality of panels forming the pool walls and floor, the panels being interconnected by elastomeric sealing members that bridge adjacent panels and contact the front faces thereof. The interconnections have a complex design that employs both a seal and a cover member. Despite these past attempts, a need remains for above ground swimming pools, spas, and related structures that do not require a liner and that are structurally sound, easy to assemble, and aesthetically pleasing.